Pinpoint Precision. Stop relying on your old, inexact, limited bubble level to do jobs that require only the most meticulous accuracy. The GemRed level tool applies an Absolute level Sensor, to ensure the accuracy of data up to ±0.2°, resolution is 0.1°. Measure slope angles 4 x 90˚ (total 360˚) range. The protractor can be instantly available, no need to calibrate by yourself.